Many people think that growing onions is not difficult, however, it is not always possible to reap a good harvest, and a lightened feather reminds that not everything is in order with the bush.
Why do white spots appear?
One of the reasons for the change in leaf color is the increased acidity of the soil. On such soil, the crop develops poorly and is not pleased with its bright greenery and large bulbs. All varieties of this plant love loose soil into which air easily penetrates.
Experienced gardeners know what to do if one of the important soil indicators does not meet the norm.In the fall, when digging up the bed, they introduce into the soil a mixture of slaked lime, plant ash and dolomite flour, which is produced on the basis of calcium. This helps reduce acidity.
If the onion feathers have turned white due to the fact that the soil was not alkalized, the problem can be eliminated by watering each bush with a glass of a special solution. To do this, 60 g of calcium nitrate must be diluted in a bucket of water. To reduce the acidity of the soil, many gardeners use ash, 200 grams of which are poured with a liter of boiling water and left for a day in a 10-liter container. A standard bucket of this solution is required per square meter of onion bed.
In addition to alkalization, wood ash saturates the crop:
- sodium;
- phosphorus;
- magnesium;
- calcium
It promotes growth and provides the onions in the garden with nutritional components for almost the entire season. Thanks to this organic substance, the water balance is normalized, the leaves acquire a healthy, rich color.
Lack of microelements
In addition to excess acid in the soil, there are other reasons why onion feathers turn white. What the plant lacks can be understood by carefully examining the bush:
- If there is insufficient nitrogen in the soil, the crop develops poorly, the leaves lose their bright color and turn yellow, and the tips become covered with white spots.
- With a deficiency of potassium, the feathers lighten and curl, greenery is poorly formed, and defective bulbs are formed.
- With an excess of peat, the plant often lacks copper, to which it reacts with whitened tips.
To eliminate the lack of nitrogen, you need to feed the soil, for this you need to dilute 3 tablespoons of calcium nitrate in a bucket of water, spray the leaves with a solution of ammonia, which is prepared in the same proportion. The deficiency of this microelement is felt by crops that grow in beds covered with straw, loosening the soil, which protects the roots from drying out and frost. You can prevent a decrease in the amount of nitrogen in the soil if you water the mulch with urea. Take half a glass of granules per bucket of water.
When there is not enough copper in the soil, the beds are treated with a composition of 0.1% copper oxychloride (10 g per 10 l). The onion root is fed with Bordeaux mixture or copper sulfate.
A white feather may indicate a potassium deficiency. Thanks to this component, greenery grows and heads are formed. If the deficiency of a microelement is not compensated, the leaves turn white and begin to curl. The mixture for feeding is prepared by dissolving 3 tablespoons of potassium chloride or 2 cups of wood ash in a bucket of water.
When does the whole plant change color?
If the bed is poorly insulated, frost can damage the onions. Then the frozen feathers turn pale. The soil needs to be better mulched and the leaves should not be picked off. In the spring, while the ground has not yet thawed, ammonium nitrate in the form of granules should be scattered over it. The onion will gradually recede and turn green.
With excess or lack of moisture, feathers turn yellow. In hot weather, it is necessary to water the crop every evening with warm, settled water. You should use no more than a bucket of liquid per square meter of bed. When it gets colder, the norm decreases by 2 times.
After rain, moisture stops for a while.
To prevent feathers from turning yellow:
- Onions should not be planted in the same place; this should be done once every 4 years.
- Before sowing, the bed is dug deeply.
- Fertilizer must be applied in a timely manner.
- Leaves that have changed color must be removed and burned.
If all the rules are followed, the plant will delight you with large bulbs. But sometimes this is not enough.
What is it sick with?
There are other reasons that lead, if not to the death of the crop, then to a deterioration in its productivity. When the spots on the feathers are covered with plaque, powdery mildew most likely has appeared. To prevent the development of this fungal disease, the leaves are sprayed with copper sulfate.
When plants are infected with downy mildew, the entire bed is treated with fungicides, the affected bushes are removed along with the head. Some gardeners advise watering the crop with a solution of potassium permanganate or salt. Repeat the procedure a couple of times.
Powdery mildew affects the plant during the wet period. From a diseased bush, spores are carried by the wind over a long distance. 3 weeks after infection, the tips of the leaves become dull. Spots appear on them, covered with a purple coating. The bulbs ripen poorly and are not stored for a long time.
Pests of culture
Feathers turn yellow when tobacco thrips infests the leaves. A microscopic insect drinks the juice from them. Since the pest overwinters in the ground or in bulbs, the heads left for planting are dipped first in hot and then in cold water. To kill insects, plants need to be sprayed with the fungicide Confidor.
The feathers change color when the stem nematode damages the bulb, causing it to rot, the leaves first turning yellow and then dying. This little worm lives in the ground for years and causes enormous damage to crops.
Vegetable growers get rid of nematodes by treating feathers with insecticides in the form of Fitoverm, Nematophagin.Some gardeners claim that they can cope with the pest by watering the soil with a marigold solution. Two kilograms of these flowers are infused in a bucket of water.
The onion fly appears when the heat lasts for a long time and there is no rain. The insect butterfly lays eggs in the ground. The light yellow caterpillars that emerge from them climb onto the feathers and chew out the tissue, causing the leaves to turn pale and wither.
They fight pests by scattering ash or tobacco on the garden bed, or spraying the ground with a solution of garlic.
The leaves turn yellow and dry out when they are eaten by the larvae of the secretive proboscis. If you do nothing, the entire crop plantation will die. This pest can be defeated only with fungicides.
To grow large bulbs that will be stored for a long time, you need to follow the rules of agricultural technology, care requirements, monitor the condition of the leaves, and promptly combat diseases and pests.
